The present invention relates to materials suitable for coating surfaces, more particularly to methods, compositions and structures pertaining to high traction or temperature-reducing materials and the utilization thereof for coating surfaces such as flight decks.
The United States Navy is developing, for aircraft carrier flight decks and other ship decks, materials having both xe2x80x9cnonskidxe2x80x9d (also spelled xe2x80x9cnon-skidxe2x80x9d) and xe2x80x9clow solar absorbingxe2x80x9d (xe2x80x9cLSAxe2x80x9d) attributes. It is desirable that materials used for coating flight decks be characterized both by nonslippage and by reduced flight deck temperatures. A high degree of flight deck traction is required for pedestrian and vehicular transportation and especially for takeoff and landing of aircraft. Moreover, the flight deck of an aircraft carrier represents an enormous solar absorber. Reducing flight deck temperatures would reduce the heat loads on the living and working spaces beneath the flight deck, ultimately reducing the air conditioning requirements and associated energy demands and increasing the habitability of these spaces. Rather than upgrade a ship""s air conditioning system, it would be preferable to effect a flight deck coating so as to reduce temperatures in the habitation spaces and working electronics spaces.
All bodies at non-zero temperature emit radiation (heat flux) as given by the Stephan-Boltzmann Law, as follows: P=xcex5"sgr"T4, where P is the radiated power (heat flux), xcex5 is the material""s spectral emissivity, "sgr" is the Stephan-Boltzmann constant (5.679*10xe2x88x928 W/(m2K)), and T is the body""s absolute temperature (xc2x0 K). There are two ways to reduce the amount of radiated power, P, viz., by either reducing the body""s temperature, or reducing the body""s spectral emissivity. Since it is unfeasible to sufficiently cool the entire flight deck, controlling the flight deck""s emissivity in the thermal emission bands is the only viable approach for thermal control. Existing LSA non-skid products have low-emissivity and perform well in the solar (0.9-2.5 xcexcm) spectral band; however, these existing materials provide an incomplete solution because they fail to address the material""s emissivity in the thermal emission (3-5 xcexcm and 8-12 xcexcm) spectral bands.
The U.S. Navy has other concerns regarding nonskid flight decks, such as durability of the nonskid formulation. Performance failures and replacement costs for nonskid decking materials are a major problem aboard ships, especially aboard aircraft carriers in high wear, high traffic areas requiring constant maintenance, e.g., landing/approach areas and approaches to elevators. Typically, these aircraft carrier flight deck areas constitute about 60,000 square feet of surface. Navy performance specifications require 10,000 landings; see the U.S. Military""s Performancc Specification, incorporated herein by reference, entitled xe2x80x9cCoating System, Non-Skid, For Roll or Spray Application (Metric),xe2x80x9d MIL-PRF-24667A (Navy), Aug. 14, 1992, superseding MIL-C-24667 (Navy), Sep. 11, 1986. However, in-service experience has seen emergent failure in as little as 3,000 landings. Totally unsatisfactory operational conditions were prevalent during the United States"" 1990-1991 Desert Shield/Desert Storm campaigns in association with excessive wear, down to the bare metal, of the flight deck; specifically, the bare metal decking in the cable arrest areas forced loss of launch certification and put the handling aircraft crew at risk. Preliminary indications are that some flight decks performed better during the United States"" 2003 war against Iraq. The operational capabilities of aircraft carriers are further degraded because of concomitant weight restrictions.
A nonskid decking material is required to be configured in such a fashion as to allow complete drainage from the flight deck (e.g., of an aircraft carrier) of water (e.g., rainwater or seawater), spilled fuel, detergents and other liquids that will detract from the nonskid qualities of the decking. Existing designs of nonskid decking have practically continuous troughs (grooves) running the entire length of the aircraft carrier deck. These conventional configurations involving longitudinal grooves succeed insofar as xe2x80x9cwind-over-the-deckxe2x80x9d driving forces bring about drainage of contaminating liquids aftward of such deck. However, such conventional designs, while worthwhile from a drainage standpoint, are less than optimal in other respects. Of special note are considerations regarding the frictional drag of aircraft tires, such as will occur during braking or during rolling over the deck while maneuvering or prior to capture. The forward motion of aircraft, parallel to the grooves, will tend to create a xe2x80x9cbow wavexe2x80x9d of liquid that moves along with the aircraft tire, thus undesirably reducing the frictional capacity of the nonskid surface.
Incorporated herein by reference are the following United States patents pertaining to coating formulations or methods related thereto, and involving nonskid or electromagnetic absorptive properties: Strait et al. U.S. Pat. No. 6,518,911 B2 issued Feb. 11, 2003; Fischer et al. U.S. Pat. No. 6,344,246 B1 issued Feb. 5, 2002; Stahovic et al. U.S. Pat. No. 5,989,328 issued Nov. 23, 1999; Parks U.S. Pat. No. 5,952,057 issued Sep. 14, 1999; Hermele et al. U.S. Pat. No. 5,686,507 issued Nov. 11, 1997; Cambon U.S. Pat. No. 4,859,522 issued Aug. 22, 1989; Kraft et al. U.S. Pat. No. 4,760,103 issued Jul. 26, 1988; Supcoe et al. U.S. Pat. No. 5,749,959 issued May 12, 1998; Supcoe U.S. Pat. No. 4,311,623 issued Jan. 19, 1982; Supcoe et al. U.S. Pat. No. 4,289,677 issued Sep. 15, 1981.
In view of the foregoing, it is an object of the present invention to provide an improved nonskid and low solar absorbing composition for covering flight decks and other surfaces.
Another object of the present invention is to provide such a composition which reduces emissivity in the thermal emission spectral bands.
Further objects of the present invention are to provide a method and a structure for covering flight decks and other surfaces with a nonskid composition, wherein the applied covering is so configured as to avoid or minimize a reduction in frictional quality of the surface.
According to typical inventive embodiments, a structure for situation upon a substrate comprises a coating composition in a cured condition. The inventive structure has formed therein an approximately linear medial groove and plural xe2x80x9cherringbonexe2x80x9d (xe2x80x9cWxe2x80x9d-shaped) grooves. Each herringbone groove traverses the medial groove so as to be divided thereby into two xe2x80x9cVxe2x80x9d-shaped groove sections. Each V-shaped groove section is formed by two approximately linear groove segments. Each groove segment is obliquely oriented with respect to the medial groove. It is frequent inventive practice that each groove segment describe, relative to the medial groove, an obtuse geometric angle in the range between approximately 120xc2x0 and approximately 150xc2x0. According to some inventive embodiments, at least a portion of the inventive structure is approximately characterized by a pyramidal texture.
It may be particularly propitious to practice the present invention in the nautical/naval realm in association with marine decks such as aircraft carrier flight decks. According to such inventive embodiments, the substrate is a marine deck which is approximately characterized by a forward deck end, an aft deck end, a port deck side, a starboard deck side and a deck length (between the forward deck end and the aft deck end). The medial groove extends at least substantially the entire length. Each V-shaped groove section points approximately toward the forward deck end. Each herringbone groove extends at least substantially the entire distance between the port deck side and the starboard deck side. In many of these and other kinds of inventive applications, the coating composition will conditionally have nonskid and low solar absorbing properties.
Although a variety of coating formulations can be inventively practiced, the inventive coating formulations may prove to be especially advantageous for marine deck applications. Generally, an inventive coating composition in a cured condition will have high solar reflectance, low thermal emittance and nonskid attributes, and will comprise in an uncured condition by percentage weight: nanolaminate pigment elements (e.g., elements having, on a very small scale, an alternating laminar arrangement of metal and polymeric materials) in the range between greater than zero percent and approximately ten percent; epoxy resin in the range between approximately fifteen percent and approximately thirty-five percent; non-nanolaminate pigment elements in the range between approximately five percent and approximately twenty percent; and abrasive elements in the range between greater than zero percent and approximately seventy percent.
The present invention provides a unique low solar absorbing (LSA) nonskid formulation suitable for coating a variety of surfaces, including aircraft carrier flight decks and other ship decks. In particular, the present invention provides a xe2x80x9chigh solar reflectance, low thermal emittancexe2x80x9d (xe2x80x9cHSR/LTExe2x80x9d) non-skid xe2x80x9cpaintxe2x80x9d formulation comprising advanced nanoscale pigmentation materials. According to many embodiments of this invention, the inventive formulation is applied in a preferential pattern to improve traction, water resistance, durability, liquid drainage and overall ship survivability. The present invention""s preferential pattern need not be practiced in association with the present invention""s nonskid formulation, but can be practiced in association with virtually any nonskid formulation.
The inventive nonskid LSA formulation includes HSR/LTE pigmentation, which acts to reduce solar absorption and heat re-radiation. According to many inventive embodiments, the HSR/LTE pigmentation includes titanium dioxide, iron oxide and phthalocyanine. Moreover, a typical inventive nonskid formulation includes specialized nanoscale pigments such as metalpolymer nanolaminate materials disclosed by Yializis et al. U.S. Pat. No. 5,912,069 issued Jun. 15, 1999, incorporated herein by reference. Furthermore, when the inventive nonskid formulation is applied in a pyramidal structural design on the nonskid decking surface(s), the present invention is especially efficacious in terms of reducing the solar absorption and the re-radiation of heat to the below deck areas.
The present invention""s concerted influence of the HSR/LTE pigmentation, the nanoscale pigmentation and the pyramidal structural configuration (of the nonskid decking itself, once cured) is especially effective in reducing the infrared signature of the carrier deck. In addition, the application of the inventive formulation as nonskid decking so as to be characterized by the present invention""s xe2x80x9cherringbonexe2x80x9d-like drainage pattern will result in significant increases in ship survivability along with improved personnel and equipment safety. Furthermore, about 4.5 acres of nonskid material typically is used to coat an aircraft carrier flight deck; application of the present invention""s relatively light (less massive) formulation may actually reduce a ship""s weight by twenty percent or more.
The present invention""s HSR/LTE nonskid formulation retains basic physical properties desirable for reflection of infrared energy, as compared with current U.S. Navy approved nonskid formulations. That is, the present invention equivalently affords high solar reflective qualities such as taught by the aforementioned Supcoe et al. U.S. Pat. No. 5,749,959, Supcoe U.S. Pat. No. 4,311,623 and Supcoe et al. U.S. Pat. No. 4,289,677, who disclose coating formulations that are in certain ways characterized by low solar absorption. In addition, the inventive LSA formulation affords certain other high solar reflection and low thermal emissivity characteristics desired by the U.S. Navy. Existing LSA formulations are only low emissive in spectral bands below 2 xcexcm; above this region, in the thermal emission bands, they are highly emissive and therefore highly absorptive. In contrast, the present invention affords high reflectivity and low emissivity in the 2-15 xcexcm range, in particular in the thermal emission (3-5 xcexcm and 8-12 xcexcm) spectral bands.
The inventors performed testing of the inventive composition and obtained acceptable readings above the 1-micron level in terms of high reflectivity and low emissivity. It is believed that the present invention""s HSR/LTE nonskid formulation products will not only enhance nonskid properties and reduce solar absorbency, but will also offer new war fighting capabilities. Deck temperatures underneath the inventive nonskid coating will be reduced, and hence the heat transfer from the deck surface to the compartment beneath will be reduced. The reduction in temperature will facilitate the cooling of air-conditioned space to a maximum of perhaps about fifteen percent. The applicability of the present invention is not limited to deck surfaces such as flight decks. In naval applications, shipboard activity and ship survivability can be improved by the inventive LSA nonskid decking as a result of increased infrared reflectance and decreased temperatures on various deck surfaces, aircraft runways, various storage compartments, heat shields, and electrical housing structures.
Inventive principles can be applied not only to ship decks such as flight decks aboard aircraft carriers, but also to myriad other surfaces aboard marine vessels and elsewhere in both military and nonmilitary contexts. The present invention is especially efficacious when practiced as a superior HSR/LTE nonskid xe2x80x9csystemxe2x80x9d combining the inventive features of the HSR/LTE nonskid coating formulation (in particular, the nanoscale materials included therein), the applied coating""s herringbone groove pattern and the applied coating""s pyramidal textural surface pattern. This inventive system represents a complete approach to providing nonskid aboard carrier ships whereby several characteristics are improved upon, particularly as pertains to safety of aircraft and personnel and to remote detection and targeting of ships (especially, in infrared detection threat bands).
This application bears some relation to copending nonprovisional U.S. patent application No. 09/372,602, filed Aug. 12, 1999, entitled xe2x80x9cVisual-Tactile Signage,xe2x80x9d joint inventors Eugene C. Fischer, Dale A. Sowell, John P. Wehrle and Albert G. Holder, incorporated herein by reference, now U.S. Pat. No. 6,696,126.
Other objects, advantages and features of this invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.